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PCI: Avoid bus reset if bridge itself is broken

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[ Upstream commit 357027786f ]

When checking to see if a PCI bus can safely be reset, we previously
checked to see if any of the children had their PCI_DEV_FLAGS_NO_BUS_RESET
flag set.  Children marked with that flag are known not to behave well
after a bus reset.

Some PCIe root port bridges also do not behave well after a bus reset,
sometimes causing the devices behind the bridge to become unusable.

Add a check for PCI_DEV_FLAGS_NO_BUS_RESET being set in the bridge device
to allow these bridges to be flagged, and prevent their secondary buses
from being reset.

Signed-off-by: David Daney <david.daney@cavium.com>
[jglauber@cavium.com: fixed typo]
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
David Daney
2017-09-08 10:10:31 +02:00
committed by Greg Kroah-Hartman
parent d3469e6166
commit 241833a3a9
1 changed files with 4 additions and 0 deletions
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4
drivers/pci/pci.c
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@@ -4214,6 +4214,10 @@ static bool pci_bus_resetable(struct pci_bus *bus)
{
struct pci_dev *dev;
if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET))
return false;
list_for_each_entry(dev, &bus->devices, bus_list) {
if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
(dev->subordinate && !pci_bus_resetable(dev->subordinate)))